Up here in Canada, I definitely prefer the Summer, for sure. You can just do so many more exciting things, and no school is a bonus. Summer>Spring>Fall>Winter, for me
I'm with Platypus. Fall is easily my favorite with perfect temperatures and gorgeous foliage. Plus, I love everything associated with Fall (Halloween, Thanksgiving, my birthday, etc.).
In Canada Winter, Spring and Fall are way too cold for me to like so summer. At least in the summer you will not get frost bite, snow which is terrible up here.